Illuminated keyswitch structure

ABSTRACT

An illuminated keyswitch structure includes a base plate, a keycap, and a light-emitting die package. The keycap is movably disposed above the base plate in a vertical direction. The light-emitting die package is disposed under the keycap and includes a plurality of light-emitting dies. The plurality of light-emitting dies are monochromatic light-emitting dies. Therein, among the plurality of light-emitting dies, three light-emitting dies that are adjacently arranged in an arrangement direction perpendicular to the vertical direction emit light of three different colors. The arrangement direction is respectively parallel to along side of each of the three adjacent light-emitting dies.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser. No. 18/098,675, filed on Jan. 18, 2023, which claims the benefit of U.S. Provisional Application No. 63/339,978, filed on May 10, 2022, and is a continuation-in-part of U.S. application Ser. No. 17/909,991, filed on Sep. 8, 2022. The contents of these applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a keyswitch structure, and more particularly to an illuminated keyswitch structure.

2. Description of the Prior Art

One-to-one illuminated keys are usually provided with a light source under each keycap. The light source is used to emit light to form a backlight. When the keycap has a permeable area corresponding to characters such as letters or symbols, the corresponding light source that is usually disposed opposite to the characters emits light toward the characters. In actual products, there are often other components between the light source and the permeable area of the keycap, such as supports, base plate, circuit board, etc., which interfere with the light transmission path and cause uneven color of the characters on the keycap. In the case where the light source can emit light of multiple colors, the problem of serious color deviation also occurs.

SUMMARY OF THE INVENTION

In view of the problems in the prior art, an objective of the invention is to provide an illuminated keyswitch structure, which uses a light-emitting die package having a plurality of light-emitting dies so that light emitted by each light-emitting dies can travel in a similar path.

An illuminated keyswitch structure of an embodiment according to the invention includes a base plate, a keycap, and a light-emitting die package. The keycap is movably disposed above the base plate in a vertical direction. The light-emitting die package is disposed under the keycap and includes a plurality of light-emitting dies. The plurality of light-emitting dies are monochromatic light-emitting dies. Therein, among the plurality of light-emitting dies, three light-emitting dies that are adjacently arranged in an arrangement direction perpendicular to the vertical direction emit light of three different colors. The arrangement direction is respectively parallel to a long side of each of the three adjacent light-emitting dies. Thereby, the plurality of light-emitting dies are packaged in a single package, so that the light emitted by each light-emitting die can travel in a similar path. Furthermore, the plurality of light-emitting dies reduce the excessive concentration of the light-emitting dies of the same color light through the arrangement, which also helps the light to illuminate the keycap evenly.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an illuminated keyswitch structure according to an embodiment.

FIG. 2 is an exploded view of the illuminated keyswitch structure in FIG. 1 .

FIG. 3 is a sectional view of the illuminated keyswitch structure along the line X-X in FIG. 1 .

FIG. 4A is a schematic diagram illustrating a top view configuration of a switch circuit board and light-emitting dies.

FIG. 4B is a schematic diagram illustrating a top view configuration of another embodiment extended from FIG. 4A.

FIG. 4C is a schematic diagram illustrating a top view configuration of another embodiment extended from FIG. 4A.

FIG. 5 is a schematic diagram illustrating a top view configuration of the switch circuit board and the light-emitting dies in FIG. 4A according to another embodiment.

FIG. 6 is a schematic diagram illustrating a top view configuration of the switch circuit board and the light-emitting dies in FIG. 4A according to another embodiment.

FIG. 7 is a top view of the illuminated keyswitch structure in FIG. 1 .

FIG. 8 is a schematic diagram illustrating a portion of a top view configuration of the switch circuit board and the light-emitting dies according to another embodiment.

FIG. 9 is a sectional view along the line Y-Y corresponding to the embodiment in FIG. 8 .

FIG. 10 is a schematic diagram illustrating an illuminated keyswitch structure according to another embodiment.

FIG. 11A is a top view of the illuminated keyswitch structure after the keycap is removed.

FIG. 11B is a schematic diagram illustrating a top view configuration of another embodiment extended from FIG. 11A.

FIG. 12 is a sectional view along the line Z-Z in FIG. 11A.

FIG. 13A is a top view of the illuminated keyswitch structure in FIG. 10 .

FIG. 13B is a top view of a portion of another embodiment extended from FIG. 13A.

FIG. 14 is a schematic diagram illustrating a light-emitting die package according to a first embodiment.

FIG. 15 is a sectional view of the light-emitting die package along the line W-W in FIG. 14 .

FIG. 16 is a schematic diagram illustrating a variation example of the light-emitting die package in FIG. 14 .

FIG. 17 is a schematic diagram illustrating a top view configuration of the light-emitting die package in FIG. 14 .

FIG. 18 is a schematic diagram illustrating a top view configuration of a light-emitting die package according to a second embodiment.

FIG. 19 is a schematic diagram illustrating a top view configuration of a light-emitting die package according to a third embodiment.

FIG. 20 is a schematic diagram illustrating a top view configuration of a light-emitting die package according to a fourth embodiment.

FIG. 21 is a schematic diagram illustrating a top view configuration of a light-emitting die package according to a fifth embodiment.

FIG. 22 is a schematic diagram illustrating a top view configuration of a light-emitting die package according to a sixth embodiment.

FIG. 23 is a top view configuration of FIG. 4A, in which the light-emitting dies are replaced by the light-emitting die package of the sixth embodiment.

FIG. 24 is a sectional view of an illuminated keyswitch structure corresponding to FIG. 23 .

FIG. 25 is a schematic diagram illustrating a top view configuration of the switch circuit board and the light-emitting die package on the base plate in a variation example of the through hole.

FIG. 26 is a schematic diagram illustrating a top view configuration of the switch circuit board and the light-emitting die package on the base plate in another variation of the through hole.

FIG. 27 is a top view configuration of FIG. 8 , in which the light-emitting dies are replaced by the light-emitting die package of the sixth embodiment.

FIG. 28 is a top view configuration of FIG. 11A, in which the light-emitting dies are replaced by the light-emitting die package of the sixth embodiment.

FIG. 29 is a top view configuration of FIG. 13B, in which the light-emitting dies are replaced by the light-emitting die package of the sixth embodiment.

FIG. 30 is a sectional view of an illuminated keyswitch structure according to an embodiment.

FIG. 31 is a sectional view of the illuminated keyswitch structure in FIG. 30 further with a mask layer.

FIG. 32 is a sectional view of a variation example of the illuminated keyswitch structure in FIG. 31 .

FIG. 33 is a top view configuration of the switch contact pad, the light-emitting die package, and the permeable area of the mask layer on the base plate in FIG. 32 .

FIG. 34 is a sectional view of an illuminated keyswitch structure corresponding to FIG. 33 .

DETAILED DESCRIPTION

Please refer to FIG. 1 to FIG. 3 . FIG. 1 is a schematic diagram illustrating an illuminated keyswitch structure according to an embodiment. FIG. 2 is an exploded view of the illuminated keyswitch structure in FIG. 1 . FIG. 3 is a sectional view of the illuminated keyswitch structure along the line X-X in FIG. 1 . An illuminated keyswitch structure 1 according to an embodiment includes a keycap 12, a base plate 14, a first support 16, a second support 18, a transparent switch circuit board 20, and one or more light-emitting dies (for example, but not limited to, three light-emitting dies 22 a, 22 b and 22 c, the light-emitting dies are used for emitting light of different color lights, such as red light, green light and blue light; besides, the light-emitting dies 22 a, 22 b and 22 c can be realized by, but not limited to, light-emitting diodes). The keycap 12 is disposed above the base plate 14. Both the first support 16 and the second support 18 are connected to and between the keycap 12 and the base plate 14 to support the keycap 12 so that the keycap 12 is movable in a vertical direction D1 (indicated by a double-headed arrow in FIG. 1 and FIG. 3 ) through the first support 16 and the second support 18. The switch circuit board 20 is placed on the base plate 14 (i.e., under the keycap 12). The light-emitting dies 22 a, 22 b and 22 c are disposed under the switch circuit board 20, e.g., fixed on a light source circuit board 24 (the light source circuit board 24 is, for example, but not limited to, a flexible printed circuit board) disposed under the base plate 14. The base plate 14 forms a corresponding through hole 142 to expose the light-emitting dies 22 a, 22 b and 22 c; in practice, the light-emitting dies 22 a, 22 b and 22 c can partially or fully enter the through hole 142. Please refer to FIG. 1 and FIG. 3 . The light-emitting dies 22 a, 22 b and 22 c are not higher than the base plate 14. The light-emitting dies 22 a, 22 b and 22 c are located within a projection of the through hole 142 in the vertical direction D1. The circuitry of the switch circuit board 20 (which is partially shown in dashed lines in FIG. 2 ) does not cover the light-emitting dies 22 a, 22 b and 22 c, so that light emitted upward by the light-emitting dies 22 a, 22 b and 22 c can pass through the switch circuit board 20 to illuminate the keycap 12.

In the embodiment, the switch circuit board 20 may be realized by a membrane circuit board, which is usually formed by stacking three layers of transparent sheets, in which the required circuitry is formed on the upper and lower transparent sheets, and the middle transparent sheet provides the insulation for the circuitry. The circuitry of the switch circuit board 20 includes switch contact pads 202 and several trace segments (the hidden profiles of which are shown in dotted lines in FIG. 2 ). The illuminated keyswitch structure 1 uses a preamble resilient dome 26 as a returning part. The resilient dome 26 aligns with the switch contact pads 202. The resilient dome 26 is disposed on the switch circuit board 20 and covers the switch contact pads 202 and the light-emitting dies 22 a, 22 b and 22 c in the vertical direction D1. The keycap 12 can be pressed (e.g., by a finger of a user) to squeeze the resilient dome 26 downward, thereby triggering the switch contact pads 202. After the external force applied to the keycap 12 is removed (e.g., the user removes his finger from the keycap 12), the squeezed resilient dome 26 can be restored to push the keycap 12 upwards back to its original position.

Please also refer to FIG. 4A. FIG. 4A is a schematic diagram illustrating a top view configuration of a portion of the switch circuit board and light-emitting dies of the illuminated keyswitch structure in FIG. 2 . Therein, the circuitry of the switch circuit board 20 and the hidden profiles of the light-emitting dies 22 a, 22 b and 22 c are shown in solid lines. The switch contact pad 202 has a non-circular profile, e.g., but not limited to, a cut-flat circular profile with a flat edge 202 a. The light-emitting dies 22 a, 22 b and 22 c are arranged in an arrangement direction D2 (indicated by a double-headed arrow in FIG. 4A). The arrangement direction D2 is parallel to the flat edge 202 a. There is a light-emitting distance d1 in a horizontal direction D3 (indicated by a double-headed arrow in the figures) between the light-emitting dies 22 a, 22 b and 22 c and the switch contact pad 202 (that is, the distance from the projection of the whole profiles of the light-emitting areas of the light-emitting dies 22 a, 22 b and 22 c on the switch circuit board 20 to the flat edge 202 a). In principle, the farther the light-emitting dies 22 a, 22 b and 22 c are away from the switch contact pads 202, the more the situation that the switch contact pads 202 shields the light emitted by the light-emitting dies 22 a, 22 b and 22 c can be reduced. In practice, the light-emitting distance d1 can be designed to be between 0.3 mm and 0.5 mm. Furthermore, in the embodiment, the cut-flat circular profile has a center 202 b and a radius 202 c. A ratio of a distance 202 d from the center 202 b to the flat edge 202 a to the radius 202 c is greater than 0.5. In principle, the switch contact pads 202 can maintain acceptable contact conduction characteristics.

Please refer to FIG. 4B and FIG. 4C. Each of FIG. 4B and FIG. 4C is a schematic diagram illustrating a top view configuration of another embodiment extended form FIG. 4A. A portion of the arc edge of the through hole 142′ of the base plate 14 (whose profile projection is shown in dashed lines in the figures) is parallel to the arc edge of the switch contact pad 202, and the other side of the through hole 142′ consists of three mutually perpendicular edges, which form a bullet-shaped through hole 142′ as a whole. In FIG. 4B, the light-emitting dies 22 a, 22 b and 22 c are all arranged in the arrangement direction D2. The light-emitting dies 22 a, 22 b and 22 c are not only adjacent to the flat edge 202 a of the switch contact pad 202, but also adjacent to a straight hole edge 142 a′ of the through hole 142′ of the base plate 14. In this case, the suitable configuration is that the arrangement direction D2 for the light-emitting dies 22 a, 22 b and 22 c is parallel (or roughly parallel) to the hole edge 142 a′ of the through hole 142′ of the base plate 14, and also parallel (or roughly parallel) to the flat edge 202 a of the switch contact pad 202. In FIG. 4C, the light-emitting dies 22 a, 22 b and 22 c are arranged in a triangle. The light-emitting die 22 a is toward the straight hole edge 142 a′ of the through hole 142′ of the base plate 14. The light-emitting die 22 c is not located within a union range of the light-emitting dies 22 a and 22 b. The light-emitting dies 22 b and 22 c are arranged straight in the arrangement direction D2 with edges parallel to each other. In this case, the arrangement direction of the at least two light-emitting dies 22 b and 22 c is parallel (or roughly parallel) to the straight hole edge 142 a′ of the through hole 142′ of the base plate 14, and also parallel (or roughly parallel) to the flat edge 202 a of the switch contact pad 202. However, it is not limited thereto in practice. For example, the at least two light-emitting dies 22 b and 22 c may be arranged in the horizontal direction D3, so that the arrangement direction of the at least two light-emitting dies 22 b and 22 c is perpendicular (or roughly perpendicular) to the straight hole edge 142 a′ of the through hole 142′ of the base plate 14, and also perpendicular (or roughly perpendicular) to the flat edge 202 a of the switch contact pad 202, but parallel to the horizontal direction D3. In another embodiment, in the bullet-shaped through hole 142′ of the base plate 14 in FIG. 4B and FIG. 4C, the three mutually perpendicular edges can be reduced as needed, and become a key-shaped through hole 142′ with an arc end portion and a narrow and long end portion. In this case, all or at least two of the light-emitting dies 22 a, 22 b and 22 may be arranged in a straight line perpendicular to the flat edge 202 a of the switch contact pad 202 and the hole edge 142 a′ at the end.

The hole edge 142 a′ of the through hole 142′ of the base plate 14 and the flat edge 202 a of the switch contact pad 202 are both heterochromatic sensitive areas. The heterochromatic sensitive area will cause the problem of uneven light mixing and color deviation. Therefore, the above technical solutions all are to dispose the plurality of light-emitting dies 22 a, 22 b and 22 c at the same side of the heterochromatic sensitive area; that is, the light-emitting dies 22 a, 22 b and 22 c are simultaneously disposed at the same side of the hole edge 142 a′ of the through hole 142′ of the base plate 14, and/or the light-emitting dies 22 a, 22 b and 22 c are simultaneously disposed at the same side of the flat edge 202 a of the switch contact pad 202. The distances from the plurality of light-emitting dies 22 a, 22 b and 22 c to the same heterochromatic sensitive area are close to each other. Since the process technology for the light-emitting dies 22 a, 22 b and 22 c has reached the millimeter or even micron level, even if the light-emitting dies 22 a, 22 b and 22 c are not arranged in a straight line, the distances to the same heterochromatic sensitive area are very close to each other. For clear display, the plurality of light-emitting dies in each figure of the present disclosure are drawn in a larger size, and the distances between the plurality of light-emitting dies are relatively large. In actual implementation, the scale of the light-emitting dies is much smaller than that in the figures of the disclosure.

In addition, in practice, the switch contact pad of the switch circuit board 20 may have different shapes. For example, as shown by FIG. 5 , the switch contact pad 203 a according to an embodiment includes a peripheral portion 2032 a and a central portion 2034 a and two connecting portions 2036 a which are located at the inner side the peripheral portion 2032 a. The two connecting portions 2036 a are located at opposite sides of the central portion 2034 a and connect the peripheral portion 2032 a and the central portion 2034 a. The peripheral portion 2032 a extends incompletely along a circular path (indicated by a dashed line in the figure) and is C-shaped. The central portion 2034 a has a circular profile. The light-emitting dies 22 a, 22 b and 22 c are located between two ends of the peripheral portion 2032 a (i.e., at the opening). The circular path passes through the light-emitting dies 22 a, 22 b and 22 c (i.e., the light-emitting dies 22 a, 22 b and 22 c are arranged on the circular path). The light-emitting dies 22 a, 22 b and 22 c are closer to the central portion 2034 a and there is a light-emitting distance d1 a between the light-emitting dies 22 a, 22 b and 22 c and the central portion 2034 a. Similarly, in practice, the light-emitting distance d1 a can be designed to be between 0.3 mm and 0.5 mm. If the light-emitting dies 22 a, 22 b and 22 c are closer to the two ends of the peripheral portion 2032 a and there is a light-emitting distance d1 a′ between the light-emitting dies 22 a, 22 b and 22 c and the peripheral portion 2032 a. Similarly, in practice, the light-emitting distance d1 a′ can also be designed to be between 0.3 mm and 0.5 mm.

For another example, as shown by FIG. 6 , the switch contact pad 203 b according to an embodiment includes a peripheral portion 2032 b and a central portion 2034 b and a connecting portion 2036 b which are located at the inner side the peripheral portion 2032 b. The connecting portion 2036 b connects the peripheral portion 2032 b and the central portion 2034 b. The peripheral portion 2032 b extends incompletely along a convex polygonal path (e.g., but not limited to a pentagonal path, indicated by dashed lines in the figure) and is roughly C-shaped. The central portion 2034 b has a convex polygonal profile (e.g., but not limited to a quadrilateral). The convex polygonal path passes through the light-emitting dies 22 a, 22 b and 22 c. The light-emitting dies 22 a, 22 b and 22 c are closer to the central portion 2034 b and there is a light-emitting distance d1 b between the light-emitting dies 22 a, 22 b and 22 c and the central portion 2034 b. Similarly, in practice, the light-emitting distance d1 b can be designed to be between 0.3 mm and 0.5 mm. If the light-emitting dies 22 a, 22 b and 22 c are closer to the peripheral portion 2032 b and there is a light-emitting distance d1 b′ between the light-emitting dies 22 a, 22 b and 22 c and the peripheral portion 2032 b. Similarly, in practice, the light-emitting distance d1 b′ can also be designed to be between 0.3 mm and 0.5 mm. Furthermore, in FIG. 5 and FIG. 6 , the convex polygonal path can also be a triangular path, a hexagonal path, etc. in practice. The profiles of the central portions 2034 a and 2034 b can also be other convex polygonal profiles, e.g. a triangular profile, a hexagonal profile, etc.

Please refer to FIG. 1 to FIG. 3 . In the embodiment, the keycap 12 has a permeable indicator area 12 a (shown by a dashed frame in the figures). Light emitted by the light-emitting dies 22 a, 22 b and 22 c can pass through the permeable indicator area 12 a to produce a visual indication effect. In practice, the permeable indicator area 12 a may be numbers, symbols, letters, characters, graphics or combinations thereof, etc.; in other words, the permeable indicator area 12 a may contain a plurality of permeable characters, and the permeable characters may be numbers, symbols, letters, characters, graphics or combinations thereof; in other words, the permeable indicator area 12 a may include a plurality of permeable characters, and the permeable character may be number, symbol, letter, character or graphic.

Please also refer to FIG. 7 (in which the hidden profiles of the light-emitting dies 22 a, 22 b and 22 c are shown in thin lines). FIG. 7 is a top view of the illuminated keyswitch structure in FIG. 1 . In the embodiment, the permeable indicator area 12 a has a lengthwise direction 12 b (e.g. the arrangement direction of the letters in the figure, indicated by a double-headed arrow in FIG. 7 ). The light-emitting dies 22 a, 22 b and 22 c are arranged under the permeable indicator area 12 a perpendicular to the lengthwise direction 12 b (that is, the arrangement direction D2 is perpendicular to the lengthwise direction 12 b), thereby reducing or eliminating the influence of uneven light mixing on the permeable indicator area 12 a caused by excessive arrangement spacing of the light-emitting dies 22 a, 22 b, and 22 c. In other words, the two ends of the permeable indicator area 12 a (and the permeable indicator area 12 a′ of the following embodiment) are heterochromatic sensitive areas, which are prone to uneven light mixing which causes color deviation of the light when exiting from the keycap 12. The permeable indicator area 12 a may include a plurality of permeable characters. The plurality of permeable characters are arranged along a long axis. The so-called heterochromatic sensitive area is the end character on both sides of the plurality of permeable characters.

Furthermore, in the embodiment, the permeable indicator area 12 a is rectangular, on which a long axis 12 c and a short axis 12 d are defined (both are shown in dashed lines in FIG. 7 ). The long axis 12 c is parallel to the lengthwise direction 12 b. The short axis 12 d is perpendicular to the lengthwise direction 12 b. The permeable indicator area 12 a is symmetrical with respect to the long axis 12 c and the short axis 12 d respectively. In terms of vertical projection, the light-emitting dies 22 a, 22 b and 22 c as a whole (that is, the plurality of light-emitting dies are regarded as a whole, the same below) pass through the long axis 12 c and the center of the light-emitting dies 22 a, 22 b, 22 c as a whole (i.e. the light-emitting die 22 b In this embodiment) is located on the long axis 12 c. In practice, the light-emitting dies 22 a, 22 b and 22 c as a whole can also be designed to pass through the center of the long axis 12 c, as shown by the rectangles in dashed lines in FIG. 7 . In this case, the light-emitting dies 22 a, 22 b and 22 c as a whole also pass through the center of the short axis 12 d. The center of the light-emitting dies 22 a, 22 b and 22 c as a whole (i.e. the light-emitting die 22 b in this embodiment) is also located at the centers of the long axis 12 c and the short axis 12 d; however, it is not limited thereto. For example, the light-emitting dies 22 a, 22 b and 22 c are offset parallel to the short axis 12 d, so that the center of the light-emitting dies 22 a, 22 b and 22 c as a whole deviates from the centers of the long axis 12 c and the short axis 12 d (for example, the light-emitting die 22 a or 22 c is located at the centers of long axis 12 c and short axis 12 d; for another example, the light-emitting dies 22 a, 22 b and 22 c are not located at the centers of long axis 12 c and short axis 12 d, as shown by rectangles in dashed lines in FIG. 7 ). In addition, in the illuminated keyswitch structure 1, although the light-emitting dies 22 a, 22 b and 22 c are arranged in a straight line, they can also be arranged in a non-linear arrangement in practice, e.g. in a triangular arrangement. In this case, when the light-emitting dies 22 a, 22 b and 22 c can be close enough to each other (which can be obtained through the actual test of the product), the influence of uneven light mixing on the permeable indicator area 12 a caused by excessive arrangement spacing of the light-emitting dies 22 a, 22 b, and 22 c can also be reduced or eliminated. The technical solutions in this embodiment are to dispose the plurality of light-emitting dies 22 a, 22 b and 22 c at the same side of the heterochromatic sensitive area; that is, the light-emitting dies 22 a, 22 b and 22 c are simultaneously disposed at the same side of the end character of the plurality of permeable characters. For the end character “L”, the light-emitting dies 22 a, 22 b and 22 c are arranged together at the same side of the end character “L”; for the end character “d” on the other side, the plurality of light-emitting dies 22 a, 22 b and 22 c are arranged together at the same side of the end character “d”. As far as the end character “L” regarded as a heterochromatic sensitive area is concerned, the arrangement direction of the light-emitting dies 22 a, 22 b and 22 c is at least partially perpendicular to the permeable indicator area 12 a, so that the distances to the same heterochromatic sensitive area (the end character “L”) are close to each other, which can reduce the color deviation. Similarly, as far as the end character “d” regarded as a heterochromatic sensitive area is concerned, the arrangement direction of the light-emitting dies 22 a, 22 b and 22 c is at least partially perpendicular to the permeable indicator area 12 a, so that the distances to the same heterochromatic sensitive area (the end character “d”) are close to each other, which can also reduce the color deviation.

In the present disclosure, a coverage space of the keycap 12 in the vertical direction D1 has a heterochromatic sensitive area. The heterochromatic sensitive area is, for example, an end of the permeable indicator area 12 a of the keycap 12. The plurality of light-emitting dies 22 a, 22 b and 22 c are located at the same side of the projection of the heterochromatic sensitive area (the end of the permeable indicator area 12 a) in the vertical direction D1. Because the distances from the plurality of light-emitting dies 22 a, 22 b and 22 c to the end of the permeable indicator area 12 a are close to each other, the light of different colors emitted by the plurality of light-emitting dies 22 a, 22 b and 22 c can travel to the end of the permeable indicator area 12 a at similar distances, which can suppress the influence of uneven light mixing and color deviation.

In the illuminated keyswitch structure 1, the switch contact pads 202 are approximately located in the central area, but it is not limited to this in practice. For example, the switch contact pads 202 are offset from the center area and are triggered by the keycap 12 (e.g. by a downwardly protruding structure) or the support (the first support 16 or the second support 18). In this case, the light-emitting dies 22 a, 22 b and 22 c can be kept far below the resilient dome 26, so that the light emitted by the light-emitting dies 22 a, 22 b and 22 c does not need to pass through the resilient dome 26, reducing light intensity attenuation. Furthermore, the circuitry of the switch circuit board 20 generally refers to a collection of a plurality of traces and a plurality of circuit elements (e.g., the switch contact pads 202 mentioned above), which are the objects that the light-emitting dies 22 a, 22 b and 22 c need to avoid. In detail, in the illuminated keyswitch structure 1, the light-emitting dies 22 a, 22 b and 22 c are closer to the switch contact pads 202 than other parts of the circuitry. However, in practice, the light-emitting dies 22 a, 22 b and 22 c may also be closer to other parts of the circuitry than the switch contact pads 202.

For example, in another embodiment, as shown by FIG. 8 (in which the hidden profile of the circuitry of the switch circuit board 20 is shown in thin lines), the light-emitting dies 22 a, 22 b and 22 c are disposed close to a trace segment 204. The trace segment 204 extends straight. The arrangement direction D2′ of the light-emitting dies 22 a, 22 b and 22 c is parallel to the trace segment 204. There is a light-emitting distance d2 (i.e. the distance from the projection of the whole profiles of the light-emitting areas of the light-emitting dies 22 a, 22 b and 22 c on the switch circuit board 20 to the trace segment 204) in the horizontal direction D3′ between the light-emitting dies 22 a, 22 b and 22 c and the trace segment 204. In practice, the light-emitting distance d2 can also be designed to be between 0.3 mm and 0.5 mm.

In practice, the switch circuit board 20 may also be disposed under the base plate 14 as required. In this case, the switch circuit board 20 is closer to the lowermost light-emitting die 22 a, 22 b and 22 c and covers a larger light-emitting range, and it is necessary to be farther away from the circuitry of the switch circuit board 20 to a greater extent. For circuit elements (e.g. the switch contact pads 202) or traces (e.g. the trace segment 204) that make up the circuitry, proper values for the light-emitting distances d1 and d2 may exceed the above-mentioned higher boundary value, 0.5 mm. In some practicable examples, the proper values for the light-emitting distances d1 and d2 are 0.59 mm, 0.66 mm and 0.78 mm. When the circuitry of the switch circuit board 20 is far away from the light-emitting dies 22 a, 22 b and 22 c, e.g., using the base plate 14 with a larger thickness, or because of other structural parts that are added due to the illuminated keyswitch structure 1 (e.g. a movable plate, a magnetic, protrusions, etc. that are used for magnetic restoration or keyboard sinking), the proper values for the light-emitting distances d1 and d2 may be less than the lower boundary value. For example, in some practicable examples, the proper values for the light-emitting distances d1 and d2 are 0.27 mm, 0.23 mm and 0.17 mm. Therefore, according to the experimental data of different product models, the light-emitting distances d1 and d2 are preferably within the range from 0.17 mm to 0.78 mm.

Besides, the switch contact pads 202 may be printed on the upper and lower transparent sheets of the switch circuit board 20, respectively. The switch contact pads 202 on the upper and lower transparent sheets may have different patterns and outer diameters. The light-emitting dies 22 a, 22 b and 22 c usually need to avoid the outermost edges of the switch contact pads 202 on the upper layer and lower layer of the switch circuit board 20; that is, the above light-emitting distance d1 have to be based on the overall outline of the switch contact pads 202 as a whole on the upper layer and lower layer.

Furthermore, please also refer to FIG. 8 and FIG. 9 . FIG. 9 is a sectional view along the line Y-Y corresponding to the embodiment in FIG. 8 . In this embodiment, the switch circuit board 20 has a through hole 206. The light-emitting dies 22 a, 22 b and 22 c are disposed opposite right to a through hole 142″ of the base plate 14 and the through hole 206, so that light emitted upward by the light-emitting dies 22 a, 22 b and 22 c can pass through the through hole 142″ and the through hole 206 to illuminate the keycap 12, which can eliminate the intensity attenuation that occurs when the light passes through the physical structure of the switch circuit board 20. In the configuration shown by FIG. 4A, if the structural design allows, the switch circuit board 20 can also form through holes opposite right to the light-emitting dies 22 a, 22 b and 22 c near the switch contact pads 202 to reduce the intensity attenuation of light.

In addition, in the embodiment, all the light-emitting dies 22 a, 22 b and 22 c for providing the keycap 12 backlight are arranged in a straight line parallel to the flat edge 202 a, but it is not limited thereto in practice. For example, the light-emitting dies 22 a, 22 b and 22 c are arranged in other arrangements (e.g. arcs, triangles, polygons, arrays, etc.); therein, the distance in the horizontal direction D3 between the light-emitting die 22 a, 22 b or 22 c closest to the switch contact pad 202 and the switch contact pad 202 is defined as the light-emitting distance. Similarly, the portion of the profile of the switch contact pad 202 close to the light-emitting dies 22 a, 22 b and 22 c is not limited to a straight line. The trace segment 204 close to the light-emitting dies 22 a, 22 b and 22 c is also not limited to a straight line. The closer the light-emitting dies 22 a, 22 b and 22 c can be disposed to the circuitry, the more the range for the light-emitting dies 22 a, 22 b and 22 c to dispose can be increased, that is, increasing the design flexibility of the permeable indicator area 12 a.

Please refer to FIG. 10 and FIG. 11A, which show an illuminated keyswitch structure 3 according to another embodiment. The illuminated keyswitch structure 3 is structurally similar to the illuminated keyswitch structure 1. The illuminated key switch structure 3 in principle follows the component symbols of the illuminated key switch structure 1. For other descriptions about the illuminated keyswitch structure 3, please refer to the relevant descriptions of the same named components and their variations in the illuminated keyswitch structure 1 in the foregoing. In the illuminated keyswitch structure 3, the first support 16 and the second support 18 are disposed opposite to each other and are light permeable, and are connected together to the bottom side of the keycap 12 and the top side of the base plate 14.

When the keycap 12 is not pressed yet, the permeable first support 16 and the permeable second support 18 are an X-shaped scissors support in an extended state (as shown in FIG. 10 or refer to FIG. 3 ). In other words, light emitted by the light-emitting dies 22 a, 22 b and 22 c disposed under the base plate 14 has different transmission paths and angles of incidence/reflection/refraction at different surface of different portions of sloping upper and lower halves and upper and lower ends of the first support 16 and the second support 18. The adjacent portions of the first support 16 and the second support 18 belong to the heterochromatic sensitive area, or the vertical space covering a gap projection G is the heterochromatic sensitive area, which is prone to uneven light mixing which causes color deviation of the light when reaching the keycap 12. If a monochromatic light source is disposed within the gap projection G (represented by dashed hatching in FIG. 11A, that is, the projection of the gap between the first support 16 and the second support 18 in the vertical direction D1) of the first support 16 and the second support 18, the light will be directly or indirectly transmitted through different portions of the first support 16 and the second support 18 to illuminate the keycap 12, which will eventually cause serious uneven illumination. If light sources of different colors such as the light-emitting dies 22 a, 22 b and 22 c are disposed in the gap projection G (or overlapping with the gap projection G), color deviation will occur at different positions of the keycap 12 due to uneven light mixing.

Please refer to FIG. 10 and FIG. 11A. Therefore, in the embodiment, all the light-emitting dies 22 a, 22 b and 22 c (whose hidden profile is shown in bold lines in FIG. 11A) for providing backlight are disposed under the first support 16 (that is, the light-emitting dies 22 a, 22 b and 22 c are located within the projection of the first support 16 in the vertical direction D1) and located within the through hole 144 (or under the base plate opposite right to the through hole 144 of the base plate 14; that is, the light-emitting dies 22 a, 22 b and 22 c are located within the projection of the through hole 144 in the vertical direction D1). The light emitted by the light-emitting dies 22 a, 22 b and 22 c travels upward from the through hole 144 and passes through the first support 16 (or passes through the through hole 144 and the first support 16) to illuminate the keycap 12. Since the light emitted by the light-emitting dies 22 a, 22 b and 22 c passes through the same support, in principle, the light is affected very similarly (e.g. intensity attenuation, divergence or deviation of travelling path, etc.), which can suppress the degree of color deviation of the light that may occur after the light passes through the structural parts. Furthermore, in the embodiment, the light emitted by the light-emitting dies 22 a, 22 b and 22 c enters the first support 16 from the lower surface 162 of the first support 16 and exits out the first support 16 from the upper surface 164 of the first support 16. The lower surface 162 and the upper surface 164 are parallel. This structural configuration also helps to suppress the degree of color deviation of the light that may occur after the light passes through the structural parts. Similarly, in practice, the light-emitting dies 22 a, 22 b and 22 c can also be changed to be disposed under the second support 18, as shown in dashed lines in FIG. 11A. In this way, as long as the gap projection G (i.e. the projection area of the gap between the first support 16 and the second support 18 in the vertical direction) of the first support 16 and the second support 18 does not overlap with the light-emitting dies 22 a, 22 b and 22 c, which can avoid color deviation. That the gap projection G of the first support 16 and the second support 18 does not overlap with the light-emitting dies 22 a, 22 b and 22 c not only means that the gap projection G does not directly overlap with any one of the light-emitting dies 22 a, 22 b and 22 c itself, but also contains the situation that the gap projection G does not pass through the gaps between any adjacent two of the light-emitting dies 22 a/22 b and 22 b/22 c (that is, the gap projection G does not overlap with or pass through the whole light-emitting dies 22 a, 22 b and 22 c). The light-emitting dies 22 a, 22 b and 22 c as a whole can be logically represented by a single convex polygonal region that can cover all light-emitting dies 22 a, 22 b and 22 c. For example, the light-emitting dies 22 a, 22 b and 22 c are not arranged in a straight line (shown by dashed rectangles in the enlarged view in FIG. 11A), and the whole can be covered by a convex hexagonal region (shown by a dashed polygon in FIG. 11A, or in terms of lines connecting their centers, they are arranged in a triangle). On the premise that the gap projection G does not overlap with or pass through the whole light-emitting dies 22 a′, 22 b′ and 22 c′, the arrangement of the light-emitting dies 22 a′, 22 b′ and 22 c′ and the gap projection G may also have a specific relative relationship. For example, at least two of the light-emitting dies 22 a′, 22 b′ and 22 c′ that are arranged in a triangle in FIG. 11A are arranged in the horizontal direction D3″ (that is, at least two of the light-emitting dies 22 a′, 22 b′ and 22 c′ are arranged parallel to the horizontal direction D3″) and perpendicular to the gap projection G (that is, the gap projection G extends roughly parallel to the arrangement direction D2″).

Besides, as shown by the three light-emitting dies 22 a′, 22 b′ and 22 c′ shown in dashed lines in FIG. 11B and arranged in a triangle on the second support 18, when the light-emitting dies 22 a′, 22 b′ and 22 c′ in dashed lines are arranged in a triangle (in terms of their central connections), the light emitting dies 22 b′ and 22 c′ are arranged in a straight line with edges parallel to each other (i.e. parallel to each other), and the light-emitting die 22 a′ is not located within the union range of the light-emitting dies 22 b′ and 22 c′ (e.g., the axes of the light-emitting die 22 b′ and the light-emitting die 22 c′ are a straight line, and the axis of the light-emitting die 22 a′ is not located on the straight line). In order to avoid local slight color deviation caused by at least two of the light-emitting dies 22 a′, 22 b′ and 22 c′ in dashed lines that are adjacent to the gap projection G between the adjacent portions of the first support 16 and the second support 18 at the same time, but have unequal distances to the gap projection G, the arrangement direction D2″ of the at least two of the light-emitting dies 22 a′, 22 b′ and 22 c′ in dashed lines that are adjacent to the gap projection G can be parallel to the gap projection G and perpendicular to the horizontal direction D3″. As for the third light-emitting dies 22 a′, 22 b′ or 22 c′ arranged in the triangle, it is roughly located on the line connecting the centers of the two light-emitting dies 22 a′, 22 b′ or 22 c′ in dashed lines. The third light-emitting dies 22 a′, 22 b′ or 22 c′ in dashed lines can be farther from the gap projection G, or can be closer to the gap projection G than the other two.

Furthermore, in the embodiment, the whole first support 16 shows a rectangular frame. The light-emitting dies 22 a, 22 b and 22 c are located under a frame portion 166 a of the rectangular frame. A projection of the frame portion 166 a in the vertical direction D1 has a lengthwise direction (in the view point of FIG. 11A, the lengthwise direction is equivalent to the arrangement direction D2″ of the light-emitting dies 22 a, 22 b and 22 c). The lengthwise direction is parallel to the arrangement direction D2″ of the light-emitting dies 22 a, 22 b and 22 c. In practice, the light-emitting dies 22 a, 22 b and 22 c can be located under a frame portion 166 b of the rectangular frame. The light-emitting dies 22 a, 22 b and 22 c are arranged parallel to the lengthwise direction (or extension direction) of the frame portion 166 b. Furthermore, the first support 16 may also be realized by frames in other geometric configurations, such as U-shaped (or n-shaped) frames.

To sum up, the above technical solutions in this embodiment are to dispose the light-emitting dies 22 a, 22 b, 22 c and 22 a′, 22 b′ or 22 c′ at the same side of the heterochromatic sensitive area, i.e. the gap projection G. At the same time, for the light-emitting dies 22 a, 22 b and 22 c, the distances to the same heterochromatic sensitive area (i.e. the gap projection G) are close to each other. For the light-emitting die 22 a′, 22 b′ or 22 c′, the distances to the same heterochromatic sensitive area (i.e. the gap projection G) are also close to each other. For example, the size of the keycap is in the order of cm, and the distances between the plurality of light-emitting dies are less than 1 mm. In this way, that the distances to the same heterochromatic sensitive area are close to each other means that the differences between the distances from each light-emitting die to the same heterochromatic sensitive area (the gap projection G) are almost negligible (e.g., the differences between the distances from each light-emitting die to the same heterochromatic sensitive area are less than 1 mm). The color deviation caused by such a small distance difference is not discernible by the human eye.

In the present disclosure, the coverage space of the keycap 12 in the vertical direction D1 has a heterochromatic sensitive area. The heterochromatic sensitive area is, for example, the gap projection G between the first support 16 and the second support 18. The plurality of light-emitting dies 22 a, 22 b and 22 c as a whole do not overlap with the gap projection G. Since the light of different colors emitted by the multiple light-emitting dies 22 a, 22 b and 22 c can travel at similar distances, the influence of the gap projection G on uneven light mixing and color deviation can be suppressed.

Furthermore, please also refer to FIG. 10 and FIG. 12 . In the embodiment, the base plate 14 has an outer plate edge 146 in the horizontal direction D3″ that is closest to the light-emitting dies 22 a, 22 b and 22 c. There is a light-emitting distance d3 between the light-emitting dies 22 a, 22 b and 22 c and the outer plate edge 146. In principle, the farther the light-emitting dies 22 a, 22 b and 22 c are away from the outer plate edge 146, the more the base plate 14 can restrain the light emitted by the light-emitting dies 22 a, 22 b and 22 c from escaping from the outer plate edge 146. In practice, the proper values for the light-emitting distance d3 of multiple models are 4.8 mm, 5.3 mm, 6.2 mm, 7.1 mm and 7.7 mm. The light-emitting distance d3 is preferably within the range from 4.8 mm to 7.7 mm. Furthermore, in the embodiment, the arrangement direction D2″ of the light-emitting dies 22 a, 22 b and 22 c is parallel to the outer plate edge 146, but it is not limited thereto in practice.

Furthermore, please also refer to FIG. 13A. FIG. 13A is a top view of the illuminated keyswitch structure in FIG. 10 , in which the hidden profiles of the light-emitting dies 22 a, 22 b and 22 c are shown in thin lines. In general, the arrangement direction of monochromatic light sources does not need to consider the lengthwise direction 12 b′ of the permeable indicator area 12 a′ of the keycap 12. However, in the case of multi-color light sources, e.g. mixing light of three colors emitted by the light-emitting dies 22 a, 22 b and 22 c into various colors that need to be presented, if the arrangement direction D2″ of the light-emitting dies 22 a, 22 b and 22 c is perpendicular to the lengthwise direction 12 b′ of the permeable indicator area 12 a′ of the keycap 12, the two light-emitting dies 22 a and 22 c on the outside provide the most sufficient light to the adjacent character section, but the character section far away from the light-emitting dies 22 a and 22 c has the problem of insufficient light, which causes color deviation on the two distal sections of the permeable indicator area 12 a′ in the lengthwise direction 12 b′. Besides, FIG. 13B is a top view of a portion of another embodiment extended form FIG. 13A, in which the light-emitting dies 22 a, 22 b and 22 c are arranged in a triangle (in terms of lines connecting their centers); that is, the long edge of the light-emitting die 22 b″ and the long edge of the light-emitting die 22 c″ are arranged perpendicular to the arrangement direction D2″, and the light-emitting die 22 a″ is not located in the union range of the light-emitting dies 22 b″ and 22 c″. If necessary, the long edge of the light-emitting die 22 a″ is parallel to the short edges of the light-emitting dies 22 b″ and 22 c″, but the long edge of the light-emitting die 22 a″ is perpendicular to the long edges of the light-emitting dies 22 b″ and 22 c″. The arrangement direction D2″ of at least two light-emitting dies 22 b″ and 22 c″ is perpendicular to the lengthwise direction 12 b′/long axis direction 12 c′ of the permeable indicator area 12 a′, also perpendicular to the horizontal direction D3″, and parallel to the short axis direction 12 d′. The light-emitting dies 22 b″ and 22 c″ are located at the same side of the same heterochromatic sensitive area, i.e., the same side of the first permeable character “L” or second permeable character “d” of the end characters, and the distances to the same heterochromatic sensitive area, i.e., the end character “L” or “d” are already close to each other, so the color deviation can be eliminated. As for the third light-emitting die 22 a′, it is disposed preferably adjacent to the center line of the short axis 12 d′ of the permeable indicator area 12 a′. In this case, there is no other light-emitting part under the permeable indicator area 12 a′, except for the light-emitting dies 22 a″, 22 b″ and 22 c″. If necessary, the line connecting the first permeable character “L” and the second permeable character “d” passes through the union range of the light-emitting dies 22 a″, 22 b″ and 22 c″, or the line connecting the first permeable character “L” and the second permeable character “d” passes through the light-emitting die 22 a″, or the center of the union range of the light-emitting dies 22 a″, 22 b″ and 22 c″ is located at the center point of the long axis of the permeable indicator area 12 a′. Overall, the light-emitting dies 22 a″, 22 b″ and 22 c″ are preferably adjacent to the geometric center of the permeable indicator area 12 a′.

In the embodiment, in the keycap 12, the lengthwise direction 12 b′ of the permeable indicator area 12 a′ above the light-emitting dies 22 a, 22 b and 22 c is perpendicular to the arrangement direction D2″, thus reducing or eliminating the influence of uneven light mixing on the permeable indicator area 12 a′ caused by the spaced arrangement of the light-emitting dies 22 a, 22 b and 22 c. In addition, for other descriptions about the relative position relationship between the light-emitting dies 22 a, 22 b and 22 c and the permeable indicator area 12 a′, please refer to the relevant descriptions of the relative position relationship between the light-emitting dies 22 a, 22 b and 22 c and the permeable indicator area 12 a and variations thereof, which will not be repeated. In addition, in the embodiment, the through hole 144 is roughly rectangular. Hole edges 144 a and 144 b of the through hole 144 are parallel to an edge of the permeable indicator area 12 a′. The arrangement direction D2″ of the light-emitting dies 22 a, 22 b and 22 c is parallel to the hole edges 144 a and 144 b (equivalent to inner plate edges) of the through hole 144, as shown by FIG. 10 and FIG. 12 . This configuration is conducive to reduction of the influence of the through hole 144 on the light field provided by the light-emitting dies 22 a, 22 b and 22 c to the permeable indicator area 12 a′. The above description also applies to the arrangement of the light-emitting dies 22 a, 22 b and 22 c relative to the through hole 142″ in FIG. 8 and FIG. 9 (in which the light-emitting dies 22 a, 22 b and 22 c are also disposed parallel to the hole edge 142 a″). Furthermore, the arrangement parallel to the hole edge can also apply to the disposition of the light-emitting dies 22 a, 22 b and 22 c relative to the through hole 142 (e.g., modified to be a rectangular hole) in the illuminated keyswitch structure 1, which will not be repeated.

In addition, in the illuminated keyswitch structure, in practice, the light-emitting dies 22 a, 22 b and 22 c can also be modified to be arranged above the base plate 14, which can avoid the interference of the base plate 14 to the light emitted by the light-emitting dies 22 a, 22 b and 22 c. In this case, the base plate 14 does not need to form a through hole corresponding to the light-emitting dies 22 a, 22 b and 22 c, which is conducive to the strength of the base plate 14. Furthermore, the light-emitting dies 22 a, 22 b and 22 c can be integrated into the circuitry of the switch circuit board 20. For example, the light-emitting dies 22 a, 22 b and 22 c are disposed directly on the lower transparent sheet of the switch circuit board 20 and are powered by the circuitry on the lower transparent sheet. The middle and upper transparent sheets form openings correspondingly, so as to expose the light-emitting dies 22 a, 22 b and 22 c. This structural configuration can eliminate the interference of the switch circuit board 20 to the light emitted by the light-emitting dies 22 a, 22 b and 22 c.

Furthermore, in the illuminated keyswitch structures 1 and 3, the first support 16 and the second support 18 are pivotally connected with each other around the pivot axis A1 (indicated by a dashed line in the figures) through their middle portions to form an X-shaped scissors support; however, it is not limited thereto in practice. For example, the first support 16 and the second support 18 can be changed to be pivotally connected with each other through their end portions, or form a V-shaped butterfly support or an inverted V-shaped support by being directly connected onto the base plate 14 through their end portions. For another example, the first support 16 and the second support 18 can be changed to be opposite and spaced apart (e.g., each of them is rotatably connected to the base plate 14), and a linkage support is used to link the first support 16 and the second support 18. Furthermore, the illuminated keyswitch structures 1 and 3 use the resilient dome 26 as the restoring force mechanism; however, it is not limited thereto in practice. For example, the restoring force mechanism is realized by a spring or a magnetic attraction mechanism.

In practice, as shown by FIG. 10 , in the embodiment, the keycap 12 has a permeable indicator area 12 a′. The permeable indicator area 12 a′ has a lengthwise direction 12 b′. The pivot axis A1 is parallel to the lengthwise direction 12 b′ of the permeable indicator area 12 a′. When the light-emitting dies 22 a, 22 b and 22 c are arranged as shown by FIG. 11A, the light of different colors emitted by the light-emitting dies 22 a, 22 b and 22 c can travel to the ends of the permeable indicator area 12 a′ at similar distances, thereby suppressing the uneven light mixing and color deviation.

Furthermore, the foregoing describes the relative position relationships of the light-emitting dies 22 a, 22 b and 22 c relative to the circuitry of the switch circuit board 20, and the first and second supports 16 and 18 with the illuminated keyswitch structures 1 and 3, respectively. In other embodiments, the illuminated keyswitch structure may also have both cases. For example, the switch contact pad 202 is located under the first support 16 or the second support 18 or adjacent to the position under the first support 16 or the second support 18, and the light-emitting dies 22 a, 22 b and 22 c are located under the first support 16 or the second support 18. For another example, the light-emitting dies 22 a, 22 b and 22 c located under the first support 16 or the second support 18 is also adjacent to the circuitry of the switch circuit board 20. Furthermore, in practice, some structural features of each embodiment may also be applied to other embodiments. For example, when the light-emitting dies 22 a, 22 b and 22 c under the base plate 14 is disposed near the circuitry of the switch circuit board 20, the light-emitting dies 22 a, 22 b and 22 c may be also near edges of the base plate 14, and hence the above illuminated keyswitch structure 3 is applicable herein.

Although the foregoing discloses the above preferably practical ranges of the light-emitting distances d1, d2 and d3 through actual implementation data, in practice, practical ranges of the light-emitting distances d1, d2 and d3 may be used with slightly reducing lighting effect relative to the above preferably practical ranges, which still can achieve a certain level of overall optical design benefits. Therefore, an addition or subtraction of 15% to 20% of the upper and lower boundary values of the preferably practical ranges of the light-emitting distances d1, d2 and d3 disclosed in the foregoing should still belong to the coverage range of the light-emitting distances d1, d2, and d3 in the foregoing.

In addition, in the above embodiments, the light-emitting dies 22 a, 22 b and 22 c (or the light-emitting dies 22 a′, 22 b′ and 22 c′, or the light-emitting dies 22 a″, 22 b″ and 22 c″) may be packed together in the same package in practice, or individually packed. Furthermore, in the case of packaging multiple light-emitting dies in a single package, the single package can package three or more light-emitting dies. For example, please refer to FIG. 14 and FIG. 15 . FIG. 14 is a schematic diagram illustrating a light-emitting die package 42 according to a first embodiment. FIG. 15 is a sectional view of the light-emitting die package along the line W-W in FIG. 14 . The light-emitting die package 42 includes a carrier 420, a plurality of light-emitting dies (including three light-emitting dies 422 a, 422 b and 422 c in the embodiment) disposed on the carrier 420, and a permeable package material 424 covering the plurality of light-emitting dies 422 a, 422 b and 422 c (in which because the permeable package material 424 is light-transmitting, the profiles of the light-emitting dies 422 a, 422 b and 422 c are shown in thin lines in FIG. 14 ). In the embodiment, the carrier 420 has side walls 420 a on its periphery to form an accommodating space 420 b. The light-emitting dies 422 a, 422 b and 422 c are accommodated in the accommodating space 420 b. The accommodating space 420 b is filled with the permeable package material 424. The permeable package material 424 covers the light-emitting dies 422 a, 422 b and 422 c. In practice, the carrier 420 may include a lead frame and a container joined with the lead frame (e.g., but not limited thereto, by injection molding). For simplification of drawings, the carrier 420 is shown by a simple structure in the figures. Taking the light-emitting die 422 a as an example, the light-emitting die 422 a has a top light-emitting surface 4222 a and four side light-emitting surfaces 4224 a. The light-emitting die 422 a emits light from the top light-emitting surface 4222 a and the side light-emitting surfaces 4224 a. The light-emitting dies 422 b and 422 c are also the same, which will not be repeated in addition. Furthermore, the disposition distances between the light-emitting dies 422 a, 422 b and 422 c depend on the actual manufacturing process, which will not be described in detail. For example, if mini-LEDs are used, the disposition distances can be hundreds of microns.

Furthermore, in the embodiment, the carrier 420 may be opaque. The carrier 420 can reflect light (e.g., using white material to make the carrier 420 or coating the inner side surfaces in the accommodating space 420 b with a reflective layer, for increasing light reflection efficiency), or the white material may be partially reflective and semi-transparent by controlling the thickness of the white material. Both help to improve the light mixing effect (that is, to increase the uniformity of the light exiting the light-emitting die package 42 from the top surface 424 a of the permeable package material 424). Furthermore, in the embodiment, light exits the light-emitting die package 42 from the top surface 424 a of the permeable package material 424 roughly in the vertical direction D1. In practice, the carrier 420 may not include the protruding side walls 420 a. For example, in FIG. 16 , the carrier 420′ is provided without protruding side walls, so that light can also be emitted out of the light-emitting die package 42 in horizontal directions D4 a and D4 b. Therein, the permeable package material 424′ has exposed side surfaces 424 b and 424 c. The side surface 424 b is parallel to the vertical direction D1 and the horizontal direction D4 a. The side surface 424 c is parallel to the vertical direction D1 and the horizontal direction D4 b. Furthermore, the horizontal directions D4 a and D4 b are perpendicular to each other; however, it is not limited thereto in practice.

For simplification of drawings, in FIG. 17 (which is a top view configuration of the light-emitting die package 42 (or 42′)), the overall outline of the light-emitting die package 42 (or 42′) is shown by a single thick box, and the light-emitting dies 422 a, 422 b and 422 c thereof are shown by thin boxes, respectively. The colors of the light emitted by the light-emitting dies 422 a, 422 b and 422 c are also indicated in the figure (e.g., red is indicated by the letter “R”, green by the letter “G”, blue by the letter “B”). As shown by FIG. 14 and FIG. 17 , in the first embodiment, the light-emitting dies 422 a, 422 b and 422 c are distributed in a plane and are monochromatic light-emitting dies. Therein, the light-emitting die 422 a emits red light, the light-emitting die 422 b emits green light, and the light-emitting die 422 c emits green light. As shown by FIG. 17 , in the light-emitting dies 422 a, 422 b and 422 c, the two adjacent light-emitting dies 422 a and 422 b which are arranged in a first arrangement direction (i.e., the horizontal direction D4 a) perpendicular to the vertical direction D1 (e.g., arranged along the horizontal dashed line in the drawing) emit light of different colors (red light and green light, respectively). In the light-emitting die package 42′ (which has the exposed side surfaces 424 b and 424 c; on the contrary, in the light-emitting die package 42, the side surfaces of the permeable package material 424 are covered by the protruding side walls 420 a), this disposition configuration makes the light emitted by the light-emitting die package 42 in a direction perpendicular to the horizontal direction D4 a not only have a single color (based on the orientation of the drawing of FIG. 17 , red light and green light can be directly received at the same time at the lower side of the light-emitting die package 42), which helps to reduce the degree of color deviation in this direction.

Similarly, the two adjacent light-emitting dies 422 b and 422 c which are arranged in a second arrangement direction (i.e., the horizontal direction D4 b) perpendicular to the vertical direction D1 (e.g., arranged along the vertical dashed line in the drawing) emit light of different colors (green light and blue light, respectively). In the light-emitting die package 42′, this disposition configuration makes the light emitted by the light-emitting die package 42 in a direction perpendicular to the horizontal direction D4 a not only have a single color (based on the orientation of the drawing of FIG. 17 , green light and blue light can be directly received at the same time at the right side of the light-emitting die package 42), which helps to reduce the degree of color deviation in this direction.

As shown by FIG. 16 , the light-emitting dies 422 a and 422 b are arranged closer to the side surface 424 b of the light-emitting die package 42′ than the other light-emitting die 422 c. The light-emitting dies 422 a and 422 b have die edges 4226 a and 4226 b parallel to the side surface 424 b, respectively. One side light-emitting surface 4224 a of the light-emitting die 422 a faces the same direction as the side surface 424 b; the same is true for the light-emitting die 422 b, which will not be repeated in addition. Furthermore, the above descriptions of the light-emitting die package 42′ are also applicable to the light-emitting die package 42, and will not be repeated in addition.

Furthermore, as shown by FIG. 17 , the light-emitting dies 422 a, 422 b and 422 c emit light of three colors (red, green and blue), the area of the top light-emitting surface corresponding to each color light is equal (in the embodiment, the top light-emitting surfaces of the light-emitting dies 422 a, 422 b and 422 c are equal). However, in practice, the light-emitting die package 42 is not limited to including three light-emitting dies. Please refer to FIG. 18 , which is a top view configuration of a light-emitting die package 43 according to a second embodiment. The light-emitting die package 43 includes four light-emitting dies, emitting green light, blue light, green light, and red light, respectively. The relevant descriptions of the aforementioned light-emitting die packages 42 and 42′ are also applicable herein, where will not be repeated in addition. For another example, as shown by FIG. 19 , a light-emitting die package 43 a according to a third embodiment also includes four light-emitting dies, emitting green light, blue light, green light, and red light, respectively. Similarly, the relevant descriptions of the aforementioned light-emitting die packages 42 and 42′ are also applicable herein, where will not be repeated in addition.

For another example, as shown by FIG. 20 , a light-emitting die package 43 b according to a fourth embodiment includes five light-emitting dies, emitting green light, blue light, red light, green light, and blue light, respectively. Similarly, the relevant descriptions of the aforementioned light-emitting die packages 42 and 42′ are also applicable herein, where will not be repeated in addition.

For another example, as shown by FIG. 21 , a light-emitting die package 43 c according to a fifth embodiment includes six light-emitting dies, emitting green light, blue light, red light, green light, blue light, and red light, respectively. Similarly, the relevant descriptions of the aforementioned light-emitting die packages 42 and 42′ are also applicable herein, where will not be repeated in addition.

For another example, as shown by FIG. 21 , a light-emitting die package 43 d according to a sixth embodiment includes eight light-emitting dies, emitting green light, red light, blue light, green light, red light, green light, blue light, and red light, respectively. Similarly, the relevant descriptions of the aforementioned light-emitting die packages 42 and 42′ are also applicable herein, where will not be repeated in addition. Furthermore, in the embodiment, the light-emitting dies of the light-emitting die package 43 d are arranged in a rectangular ring. Any two adjacent light-emitting dies along the rectangular ring emit light of different colors.

In the light-emitting die packages 42, 42′, 43 a, 43 b, 43 c and 43 d of the above embodiments, each light-emitting die has at least one side facing outwards. For example, in the light-emitting die package 43 d shown by FIG. 22 (based on the orientation of the drawing of FIG. 22 ), the right and upper sides of the right light-emitting die of blue light face outwards, the right side of the right light-emitting die of green light faces outwards, the right and lower sides of the right light-emitting die of red light face outwards, the upper side of the middle light-emitting die of red light faces outwards, the lower side of the middle light-emitting die of green light faces outwards, and so on. This configuration helps to improve the utilization of the light emitted by the light-emitting die package through its side surfaces. However, it is not limited thereto in practice. For example, a light-emitting die is also disposed at the location indicated by a dashed box in FIG. 22 .

In actual applications, the above light-emitting die packages 42, 42′, 43 a, 43 b, 43 c and 43 d may directly replace the above light-emitting dies 22 a, 22 b and 22 c, the above light-emitting dies 22 a′, 22 b′ and 22 c′ or the above light-emitting dies 22 a″, 22 b″, 22 c″ and be disposed in the illuminated keyswitch structures 1 and 3. For example, the light-emitting die package 43 d (as shown by FIG. 19 ) replaces the light-emitting dies 22 a, 22 b and 22 c (of the illuminated keyswitch structure 1) in FIG. 4A and is fixed on the light source circuit board 24 (also referring to FIG. 2 ). The top view configuration thereof is shown as FIG. 23 ; the sectional view thereof is shown as FIG. 24 (equivalent to the case that the light-emitting dies 22 a, 22 b and 22 c in FIG. 3 are replaced with the light-emitting die package 43 d). The circuitry (including the switch contact pads 202) of the switch circuit board 20 does not overlap with the light-emitting die package 43 d. In the light-emitting die package 43 d, some of the plurality of light-emitting dies (i.e., based on the orientation of the drawing of FIG. 17 , the light-emitting die of blue light, the light-emitting die of green light, and the light-emitting die of red light on the lower side) are closer to the flat edge 202 a of the switch contact pad 202 than the other light-emitting dies in the horizontal direction D3 (perpendicular to the vertical direction D1) and are arranged parallel to the flat edge 202 a (i.e., arranged in the direction D2).

Furthermore, as shown by FIG. 24 , the light-emitting die package 43 d is located in the through hole 142 of the base plate 14. The vertical projections of the switch contact pad 202 and the light-emitting die package 43 d on the base plate 14 are located within the through hole 142. The light-emitting die package 43 d is not higher than an upper surface 142 c of the base plate 14 in the vertical direction D1 (that is, the top surface of the light-emitting die package 43 d (e.g., the top surface 424 a of the permeable package material 242, referring to FIG. 14 or FIG. 15 ) is lower than or equal to the upper surface 142 c).

In this embodiment, the through hole 142 (as shown by FIG. 2 ) is circular; however, it is not limited thereto. For example, in a variation example of the through hole 142, part of the arc edge of the through hole 142′ (the profile projection of which is shown in dashed lines in FIG. 23 ) of the base plate 14 is parallel to the arc edge of the switch contact pad 202, and at the other side of the through hole 142, three edges are perpendicular to each other, thereby constituting a bullet-shaped through hole as a whole. Therein, based on the orientation of the drawing of FIG. 23 , the adjacent light-emitting dies on the left side of the light-emitting die package 43 d (i.e., the light-emitting die of blue light, the light-emitting die of red light, and the light-emitting die of green light) are closer to the hole edge 142 b′ than the other light-emitting dies in a horizontal direction (equivalent to the direction D2) perpendicular to the vertical direction D1 and are arranged parallel to the straight hole edge 142 b′ (i.e., arranged in the direction D3, or arranged perpendicular to the straight hole edge 142 a′). Thereby, the hole edge 142 b′ has similar shading conditions for each of the light-emitting dies on the left of the light-emitting die package 43 d, which helps to reduce the influence of the hole edge 142 b′ on the uniformity of the backlight provided by the light-emitting die package 43 d. For the straight hole edges 142 a′ and 142 c′, the light-emitting die package 43 d also has the light-emitting dies that are adjacent to the straight hole edges 142 a′ and 142 c′ and are arranged parallel to the straight hole edges 142 a′ and 142 c′, which will not be described in addition.

For another example, in a variation example of the through hole 142, as shown by FIG. 25 , the through hole 143 (the profile of which is shown in bold lines in the figure) of the base plate 14 includes a main hole portion 143 a and two extension portion 143 b extending from two sides of the main hole portion 143 a. The vertical projection (shown in thin lines in the figure) of the switch contact pad 202′ on the base plate 14 is located within the main hole portion 143 a. The vertical projection (shown in thin lines in the figure) of the light-emitting die package 43 d on the base plate 14 is located within one of the extension portions 143 b. In the embodiment, another light-emitting die package 43 d (shown in dashed lines in the figure) is disposed according to the other extension portions 143 b. Thereby, the switch contact pad 202′ also can avoid covering the light-emitting die package 43 d directly. In addition, the two extension portions 143 b are arranged at 180 degrees; however, it is not limited thereto in practice. For example, the two extension portions 143 b can be arranged at 120 degrees (logically, this still belongs to the arrangement on both sides of the main hole part 143).

For another example, in a variation example of the through hole 142, as shown by FIG. 26 , the base plate 14 has a through hole 143′ (the profile of which is shown in bold lines in the figure). The vertical projection (shown in thin lines in the figure) of the switch contact pad 202″ on the base plate 14 is located outside the through hole 143′ and beside the through hole 143′. The vertical projection (shown in thin lines in the figure) of the light-emitting die package 43 d on the base plate 14 is located within the through hole 143′. Thereby, the switch contact pad 202″ also can avoid covering the light-emitting die package 43 d directly. Furthermore, the through hole 143′ is a circular sector and (in the view point of FIG. 26 ) extends along the inner edge of the through hole 143′. In addition, in practice, it is practicable to dispose another through hole 143′ (shown in dashed lines in the figure), and another light-emitting die package 43 d (shown in dashed lines in the figure) is also disposed according to this through hole 143′. Furthermore, in practice, the central angle corresponding to the circular sector is not limited to the case shown in the figure that is less than 180 degrees. The two through holes 143′ are not limited to configurations with the same profile and symmetrical disposition. In the embodiment, the through hole 143′ is disposed to avoid the circuitry layout, so the through holes 143′ may be formed in a single C-shaped profile in practice (for example, modify the leads of the switch contact pad 202″ in the figure so that they are on the same side); however, it is not limited thereto in practice. Furthermore, in practice, the profile of the through hole 143′ is not limited to a circular sector.

In the foregoing, as shown by FIG. 8 , the light-emitting dies 22 a, 22 b and 22 c and the trace segment 204 are staggered (i.e., not overlapping in the vertical direction D1). Similarly, in actual applications, the light-emitting dies 22 a, 22 b and 22 c may be replaced with the light-emitting die package 43 d, as shown by FIG. 27 . The trace segment 204 extends straight. In the light-emitting die package 43 d, some of the light-emitting dies (i.e., based on the orientation of the drawing of FIG. 27 , the left light-emitting die of green light, the left light-emitting die of red light, the left light-emitting die of blue light (e.g. referring to FIG. 22 )) that are closer to the trace segment 204 than the other light-emitting dies in the horizontal direction D3′ (perpendicular to the vertical direction D1) are arranged parallel to and near to the trace segment 204 (i.e., arranged in the direction D2). The relevant descriptions about FIG. 8 and FIG. 9 in the foregoing are also applied herein if they are applicable, where will not be repeated in addition.

In the foregoing, as shown by FIG. 11A, the light-emitting dies 22 a, 22 b and 22 c are located under one of the supports (e.g., the first support 16). In actual applications, the light-emitting dies 22 a, 22 b and 22 c may be replaced with the light-emitting die package 43 d, as shown by FIG. 28 . In the light-emitting die package 43 d, some of the light-emitting dies (i.e., based on the orientation of the drawing of FIG. 28 , the left light-emitting die of green light, the left light-emitting die of red light, the left light-emitting die of blue light (e.g. referring to FIG. 22 )) that are closer to the gap projection G (which has a lengthwise direction equivalent to the direction D2″; the gap projection G extends roughly in the lengthwise direction) than the other light-emitting dies in a horizontal direction D3″ perpendicular to the vertical direction D1 are arranged parallel to the lengthwise direction and have a die edge (e.g., the left edges of the above light-emitting dies) parallel to the lengthwise direction. Thereby, the gap projection G has similar shading conditions for each of the light-emitting dies on the left of the light-emitting die package 43 d, which helps to reduce the influence of the gap projection G on the uniformity of the backlight provided by the light-emitting die package 43 d. Furthermore, in the embodiment, the light-emitting die package 43 d is completely below the first support 16, so that the light emitted by each light-emitting die in the light-emitting die package 43 d can travel in a similar path, thereby reducing the degree of color deviation that may occur after the light passes through the first support 16. The relevant descriptions about FIG. 11A in the foregoing are also applied herein if they are applicable, where will not be repeated in addition. For example, the light-emitting die package 43 d can be changed to be disposed under the second support 18 (e.g., the light-emitting die package 43 d shown in dashed lines in the figure).

In the foregoing, as shown by FIG. 7 , FIG. 13A and FIG. 13B, the light-emitting dies 22 a, 22 b and 22 c as a whole overlaps with the permeable indicator areas 12 a and 12 a′ in the vertical direction D1. In actual applications, the light-emitting dies 22 a, 22 b and 22 c may be replaced with the light-emitting die package 43 d. As shown by FIG. 29 , the permeable indicator area 12 a′ is rectangular and thereon defines a long axis 12 c′ and a short axis 12 d′ (indicated by chain lines in the figure). The long axis 12 c′ is parallel to the lengthwise direction 12 b′. The short axis 12 d′ is perpendicular to the lengthwise direction 12 b′ (and also parallel to the direction D2″). The geometric center of the permeable indicator area 12 a′ (equivalent to the intersection of the long axis 12 c′ and the short axis 12 d′) overlaps with the light-emitting die package 43 d in vertical direction D1 (or the geometric center falls within the range of light-emitting die package 43 d). Furthermore, in the embodiment, the geometric center of the permeable indicator area 12 a′ coincides with the geometric center of the light-emitting die package 43 d; however, it is not limited thereto in practice. For example, the geometric center of the light-emitting die package 43 d deviates from the geometric center of the permeable indicator area 12 a′, referring to the light-emitting die package 43 d shown in dashed lines in the figure. Therein, in this case, the vertical projection of the whole light-emitting die package 43 d still falls within the extent of the permeable indicator area 12 a′; however, it is not limited thereto in practice. For example, the vertical projection of the whole light-emitting die package 43 d exceeds the extent of the permeable indicator area 12 a′ (e.g., in FIG. 13A, both vertical projections of the light-emitting dies 22 a and 22 c are beyond the extent of the permeable indicator area 12 a′, so that the vertical projection of the light-emitting dies 22 a, 22 b and 22 c as a whole partially exceeds the extent of the permeable indicator area 12 a′). Furthermore, in the embodiment, the permeable indicator area 12 a′ includes a plurality of permeable characters (e.g. “Legend” in the figure) arranged along the lengthwise direction 12 b′. In the light-emitting die package 43 d, the die edges of the light-emitting dies are parallel to or perpendicular to the lengthwise direction 12 b′ (for example, for the light-emitting die of green light in the upper left corner, its upper and lower side edges are parallel to the lengthwise direction 12 b′ (i.e., parallel to the long axis 12 c′), and its left and right side edges are perpendicular to the lengthwise direction 12 b′). The relevant descriptions about FIG. 7 , FIG. 13A and FIG. 13B in the foregoing are also applied herein if they are applicable, where will not be repeated in addition.

The foregoing is described with the light-emitting die package 43 d replacing the light-emitting dies 22 a, 22 b and 22 c as an example. In principle, the light-emitting die packages 42, 42′, 43 a, 43 b, 43 c and 43 d can also be used to replace the above light-emitting dies 22 a, 22 b and 22 c, the above light-emitting dies 22 a′, 22 b′ and 22 c′, or the above light-emitting dies 22 a″, 22 b″ and 22 c″ and be applied to each of the above embodiments, which will not be further described in detail.

In addition, in practice, the above embodiments may be provided with a light-guiding sheet to guide and mix light emitted by the light-emitting die packages 42, 42′, 43 a, 43 b, 43 c and 43 d and the light-emitting dies 22 a, 22 b, 22 c, 22 a′, 22 b′, 22 c′, 22 a″, 22 b″ and 22 c″. Please refer to FIG. 30 . An illuminated keyswitch structure 4 shown by FIG. 30 is similar to the illuminated keyswitch structure 1, so the illuminated keyswitch structure 4 follows the component symbols of the illuminated key switch structure 1. For other descriptions about the illuminated keyswitch structure 4, please refer to the relevant descriptions of the illuminated keyswitch structure 1 and variations thereof in the foregoing, which will not be repeated in addition. A main difference between the illuminated keyswitch structure 4 and the illuminated keyswitch structure 1 is roughly that the illuminated keyswitch structure 4 further includes a light-guiding sheet 28 that is disposed under the base plate 14. The light-guiding sheet 28 has an accommodating recess 282 (e.g., realized by a through hole). The light-emitting die package 43 d (or other light-emitting die packages 42, 42′, 43 a, 43 b and 43 c) is located in the accommodating recess 282, so that the light emitted by the light-emitting die package 43 d enters the light-guiding sheet 28 from an inner wall surface 282 a of the accommodating recess 282. The light entering the light-guiding sheet 28 can leave the light-guiding sheet 28 from an upper surface 284 of the light-guiding sheet 28. As shown by FIG. 30 , the base plate 14 does not cover the light-guiding sheet 28 at its through hole 142, so the light can illuminate the keycap 12 upwards through the through hole 142. In terms of structural properties, the base plate 14 has an opaque effect in principle, and therefore can be used as a mask layer at the same time. In addition, in the embodiment, the projection of the switch contact pad 202 of the switch circuit board 20 on the base plate 14 is also located within the through hole 142; however, it is not limited thereto in practice. For example, the switch contact pad 202 is moved to another place (away from the through hole 142) or there is also a physical structure of the base plate 14 under the switch contact pad 202, so that the light exiting from the upper surface 284 of the light-guiding sheet 28 will not directly irradiate the switch contact pad 202, which helps to reduce the possible influence of the light reflected by the circuitry of the circuit board 20 (e.g., the color of the reflected light is changed).

Furthermore, in practice, a mask layer 30 may be disposed on the upper surface 284 of the light-guiding sheet 28, for a shielding design for the light-guiding sheet 28, as shown by FIG. 31 . In practice, the mask layer 30 can be realized by an opaque thin sheet disposed right above the light-emitting die package 43 d. The mask layer 30 covers the accommodating recess 282 (together with the light-emitting die package 43 d accommodated therein) and forms a permeable area 302 a at the desired area (e.g. by making holes on this thin sheet), e.g. corresponding to the through hole 142. The quantity and profile of the permeable area 302 a can be designed according to product requirements, without being troubled by the structural design of the base plate 14 itself (such as the light leakage caused by the hollow structure for forming the connection structure of the supports). In the embodiment, the vertical projection of the permeable area 302 a on the base plate 14 is located within the through hole 142. In addition, in practice, the accommodating recess 282 is not limited to a through hole. For example, the accommodating recess may be realized by a blind hole or recess. In this case, the accommodating recess opens downwards, and will not communicate with the upper surface 284. The mask layer 30 may be realized by an opaque coating layer coated on the upper surface 284 (e.g., but not limited to, by printing).

Please refer to FIG. 32 and FIG. 33 ; therein, in FIG. 33 , the profile of the switch contact pad 203 c is shown in thin lines, the profile of the light-emitting die package 43 d is shown by a bold frame, and the profile of the accommodating recess 282 of the light-guiding sheet 28′ and the profile of the permeable areas 302 b of the mask layer 30′ are shown in dashed lines. In this example, the vertical projections of the switch contact pad 203 c, the accommodating recess 282 of the light-guiding sheet 28′ (together with the light-emitting die package 43 d), and the permeable area 302 b of the light-guiding sheet 28′ on the base plate 14 are located in the through hole 142. Furthermore, the light-emitting die package 43 d is located under the switch contact pad 203 c. On the other hand, the switch contact pad 203 c and the light-emitting die package 43 d overlap in the vertical direction D1. The permeable areas 302 b of the mask layer 30′ are disposed on the periphery of the projection of the light-emitting die package 43 d on the mask layer 30′. In the embodiment, the permeable area 302 b is a circular sector (as shown by FIG. 33 ) and extends around the projection of the light-emitting die package 43 d on the mask layer 30′. In the embodiment, the permeable area 302 b also extends around the projection of the switch contact pad 203 c on the mask layer 30′; the permeable area 302 b extends roughly beside the projection of the switch contact pad 203 c on the mask layer 30′. Furthermore, in practice, the central angle corresponding to the circular sector is not limited to the case shown in the figure that is less than 180 degrees. The two permeable areas 302 b are not limited to configurations with the same profile and symmetrical disposition. In the embodiment, the permeable area 302 b is disposed to avoid the circuitry layout, so the permeable areas 302 b may be formed in a single C-shaped profile in practice (for example, modify the leads of the switch contact pad 203 c in the figure so that they are on the same side); however, it is not limited thereto in practice. Furthermore, in practice, the profile of the permeable area 302 b is not limited to a circular sector. On the other hand, a vertical projection of an opaque portion of the mask layer 30 on the base plate 14 at least partially falls within the through hole 142. For example, as shown by FIG. 32 , a portion of the mask layer 30 above the light-emitting die package 43 d (which may be defined as an impermeable area of the mask layer 30) falls within the through hole 142. For another example, as shown by FIG. 32 , a left portion of the mask layer 30 (which may be defined as another impermeable area of the mask layer 30) forms a portion of the profile of the permeable area 302 b; the vertical projection of the left portion on the base plate 14 partially falls within the through hole 142.

In addition, in the embodiment, in practice, there may also be a physical structure of the base plate 14 between the switch contact pad 203 c and the mask layer 30′, for providing structural support for the switch contact pad 203 c, as shown by FIG. 34 . In this embodiment, the base plate 14 forms a through hole 145 corresponding to the permeable area 302 b to expose the corresponding permeable area 302 b. In practice, the through hole 145 may be (but is not limited to) a circular sector and similar in profile to the permeable area 302 b. The vertical projection of the switch contact pad 203 c on the base plate 14 is located outside the through hole 145 and beside the through hole 145.

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. 

What is claimed is:
 1. An illuminated keyswitch structure, comprising: a base plate; a keycap, movably disposed above the base plate in a vertical direction; and a light-emitting die package, disposed under the keycap and comprising a plurality of light-emitting dies, the plurality of light-emitting dies being monochromatic light-emitting dies, wherein among the plurality of light-emitting dies, three light-emitting dies that are adjacently arranged in a first arrangement direction perpendicular to the vertical direction emit light of three different colors, and the first arrangement direction is respectively parallel to a long side of each of the three adjacent light-emitting dies.
 2. The illuminated keyswitch structure according to claim 1, wherein the light-emitting die package comprises a permeable package material that covers the plurality of light-emitting dies, and the permeable package material has a side surface that is parallel to the first arrangement direction and the vertical direction.
 3. The illuminated keyswitch structure according to claim 1, wherein the three adjacent light-emitting dies of the plurality of light-emitting dies are arranged adjacent to a side surface of the light-emitting die package.
 4. The illuminated keyswitch structure according to claim 1, wherein the light-emitting die package comprises a carrier, the carrier has side walls to form an accommodating space, and the plurality of light-emitting dies are accommodated in the accommodating space.
 5. The illuminated keyswitch structure according to claim 1, wherein the plurality of light-emitting dies are arranged in a rectangular ring, and any two adjacent light-emitting dies along the rectangular ring emit light of different colors.
 6. The illuminated keyswitch structure according to claim 1, further comprising a switch circuit board that is light-transmitting and disposed above the light-emitting die package, wherein the switch circuit board comprises a permeable carrying plate structure and circuitry carried on the permeable carrying plate structure, and the switch circuit board and the light-emitting die package do not overlap in the vertical direction.
 7. The illuminated keyswitch structure according to claim 1, further comprising a switch circuit board that is light-transmitting and disposed above the light-emitting die package, wherein the switch circuit board comprises a switch contact pad, the switch contact pad has a flat edge, and the three adjacent light-emitting dies of the plurality of light-emitting dies are arranged adjacent to and parallel to the flat edge.
 8. The illuminated keyswitch structure according to claim 1, further comprising a first support and a second support which are pivotally connected with each other, wherein each of the three adjacent light-emitting dies of the plurality of light-emitting dies does not overlap with a gap projection of the first support and the second support in the vertical direction.
 9. The illuminated keyswitch structure according to claim 1, further comprising a switch circuit board, wherein the switch circuit board and the base plate are stacked, the switch circuit board is disposed above the light-emitting die package, the base plate a through hole, the switch circuit board comprises a switch contact pad, and vertical projections of the switch contact pad and the light-emitting die package on the base plate fall within the through hole.
 10. The illuminated keyswitch structure according to claim 9, wherein the through hole comprises a main hole portion and an extension portion extending from a side of the main hole portion, the vertical projection of the switch contact pad on the base plate falls within the main hole portion, and the vertical projection of the light-emitting die package on the base plate falls within the extension portion.
 11. The illuminated keyswitch structure according to claim 1, further comprising a switch circuit board that is light-transmitting, wherein the switch circuit board and the base plate are stacked, the switch circuit board is disposed above the light-emitting die package, the base plate has a through hole, the switch circuit board comprises a switch contact pad, a vertical projection of the light-emitting die package on the base plate falls within the through hole, and a vertical projection of the switch contact pad on the base plate is located outside the through hole.
 12. The illuminated keyswitch structure according to claim 1, further comprising a switch circuit board that is light-transmitting, wherein the switch circuit board and the base plate are stacked, the switch circuit board is disposed above the light-emitting die package, the switch circuit board a trace segment extending straight, and the three adjacent light-emitting dies of the plurality of light-emitting dies are arranged adjacent to and parallel to the trace segment.
 13. The illuminated keyswitch structure according to claim 1, wherein the keycap has a permeable indicator area, the permeable indicator area has a lengthwise direction, the permeable indicator area comprises a plurality of permeable characters arranged along the lengthwise direction, and the permeable indicator area and the light-emitting die package at least partially overlap in the vertical direction.
 14. The illuminated keyswitch structure according to claim 1, wherein the keycap has a permeable indicator area, the permeable indicator area has a lengthwise direction, and the three adjacent light-emitting dies of the plurality of light-emitting dies have edges perpendicular to the lengthwise direction.
 15. The illuminated keyswitch structure according to claim 1, further comprising a light-guiding sheet that is disposed under the base plate, wherein the light-guiding sheet has an accommodating recess, the light-emitting die package is located in the accommodating recess, and light emitted by the light-emitting die package enters the light-guiding sheet from an inner wall surface of the accommodating recess.
 16. The illuminated keyswitch structure according to claim 1, further comprising a mask layer that is disposed directly above the light-emitting die package and covers the light-emitting die package.
 17. The illuminated keyswitch structure according to claim 1, further comprising a mask layer that covers the light-emitting die package, wherein the mask layer has at least one permeable area disposed on a periphery of a projection of the light-emitting die package on the mask layer.
 18. The illuminated keyswitch structure according to claim 17, wherein the base plate has a through hole, and a vertical projection of the permeable area on the base plate falls within the through hole.
 19. The illuminated keyswitch structure according to claim 17, wherein the base plate has a through hole, and a vertical projection of an impermeable area of the mask layer on the base plate at least partially falls within the through hole.
 20. The illuminated keyswitch structure according to claim 1, wherein the base plate has a through hole, the through hole has a straight hole edge, at least two adjacent ones of the plurality of light-emitting dies are arranged parallel to the straight hole edge, and the three adjacent light-emitting dies of the plurality of light-emitting dies are arranged perpendicular to the straight hole edge. 